export default {
  // 为当前模块开启命名空间
  namespaced: true,
  // 模块的store数据
  state: () => ({
    // 购物车的数组，用来存储购物车中每个商品的信息对象
    // 每个商品的信息对象，都包含如下 6 个属性：
    // { goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state }
    cart: JSON.parse(uni.getStorageSync('cart') || '[]')
  }),
  // 模块的mutations 方法
  mutations: {
    addToCart (state, goods) {
      const findResult = state.cart.find((x) => x.goods_id === goods.goods_id)
      if (!findResult) {
        state.cart.push(goods)
      }else{
        findResult.goods_count++
      }
       this.commit('m_cart/saveToStorage')
    },
    // 持久化保存购物车里的商品
    saveToStorage(state) {
       uni.setStorageSync('cart', JSON.stringify(state.cart))
    },
    // 处理购物车中的选中状态
    updateGoodsState (state, goods) {
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
      if (findResult) {
        findResult.goods_state = goods.goods_state
        this.commit('m_cart/saveToStorage')
      }
    },
    // 更新商品的数量
    updateGoodsCount (state, goods) {
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
      if (findResult) {
        findResult.goods_count = goods.goods_count
        this.commit('m_cart/saveToStorage')
      }
    },
    // 根据商品id删除商品
    removeGoodsById (state, goods_id) {
      state.cart = state.cart.filter(x => x.goods_id !== goods_id)
      this.commit('m_cart/saveToStorage')
    },
    // 更新购物车中的勾选状态
    updateAllGoodsState (state, newState) {
      state.cart.forEach(x => x.goods_state = newState)
      this.commit('m_cart/saveToStorage')
    }
  },
  // 模块的getters
  getters: {
    // 购物车中所有商品的总数量
    total (state) {
      return state.cart.reduce((total, item) => total += item.goods_count, 0)
    },
    // 勾选商品的总数量
    checkedCount (state) {
      return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0)
    },
    // 计算勾选商品的总价格
    checkGoodsAmount (state) {
      return state.cart.filter(x => x.goods_state).reduce((price, item) => price += item.goods_count * item.goods_price, 0).toFixed(2)
    }
  }
}